The obvious upgrades are.... Factory titanium turnbuckles with RPM rod ends.. So that turnbuckles don't bend ..pop off.... Then factory threaded shocks .so much better to set up..preferably V2...
Battery should be Lipo about 5000 mah.. Cheap Turnigy nano tech from Hobby king or expensive such as LRP or Reedy....but have a look on here, there are often some good second hand packs for sale..
Most important item is tyres..depending on what your intend racing or bashing..lots of advice on here..
Good luck... The B4.1 is a good car..
